[ScopInliner] Fix hidden overload warning. NFC.

By exposing the the hidden member, but as private.

llvm-svn: 311550

polly/lib/Transform/ScopInliner.cpp

@@ -30,6 +30,8 @@ extern bool polly::PollyAllowFullFunction;
 
 namespace {
 class ScopInliner : public CallGraphSCCPass {
+  using llvm::Pass::doInitialization;
+
 public:
   static char ID;